DESCRIPTION OF THE PRIOR ART
Among the synthetic fibers produced on industrial scales at present, polyester fibers which is mainly composed of polyethylene terephthalate or polyamide fibers mainly composed of nylon 66 have received particularly wide acceptance, because of their excellent properties.
However, the polyester fibers have such drawbacks as poor dyeability, poor moisture transport and excessively high Young's modulus (initial modulus). A high initial modulus is objectionable in that it causes poor drapeability of the fabric prepared from the fibers.
The polyamide fibers, on the other hand, have a low initial modulus significantly lower than that of the polyester fibers, but the polyamide is moisture sensitive which results in poor dimentional stability to moisture.
Furthermore, a common and important drawback in the two fibers is that they are apt to accumulate electrostatic charge. If the hygroscopicity of both fibers could be enhanced, it would be possible to produce anti-static fabrics having increased comfort characteristics.
The lactam terpolymer used in this invention e.g. a lactam-polyol-polyacyl lactam or acyl polylactam, has good antistatic properties and good moisture transport properties, but it would be desirable to provide for improved dimensional stability to moisture.
Accordingly, it is apparent that if a polymer composition could be provided which is free from the foregoing drawbacks, interalia, the static charge accumulation, while retaining the excellent properties of the polyester and polyamide, the shaped articles prepared therefrom such as fibers and films will have very high commercial value.
Therefore, the object of this invention is to provide a resinous composition which gives the novel shaped articles including fibers having the above-described desirable characteristics, as well as a process for the preparation of such shaped articles from the composition.
Since polyesters and polyamides are chemically incompatible, it has not been possible in the past to create melt blends of a polyester and a polyamide having the abovedescribed desirable properties or to use them in fiber or fabrics such as non-woven fabrics.
The three component blends of this invention can be accomplished by any of the following methods.
1. The three polymer chips are well mixed and the mixture is converted into fibrous or shaped articles according to the accepted practice, using a conventional melt-spinning or molding machine.
2. The polymers are separately melted, and blended in the molten state.
3. A solid mixture of the three polymers is melt blended in a conventional extruder to form chips or pellets, which are then converted into fibrous or shaped articles by means of a conventional melt-spinning or molding machine.
The composition of this invention can be converted into filaments and staple by melt-spinning. It is also possible to use the composition as a component of composite fibers.